Baghdad, Iraq ? The U.S. military will not hand over jails or individual detainees to Iraqi authorities until they demonstrate higher standards of care, an American official said Sunday, two weeks after the discovery of 120 abused Iraqi prisoners.

Meanwhile, bloodshed claimed at least 18 lives across Iraq, including two U.S. and five Iraqi soldiers killed by bombings in Baghdad.

Lt. Col. Barry Johnson said detention facilities in Iraq will be transferred over time to Iraqi officials but they must first show that the rights of detainees are safeguarded and that international law on the treatment of prisoners is being followed.

“A specific timeline for doing this is difficult to project at this stage with so many variables,” said Johnson, a military spokesman. “The Iraqis are committed to doing this right and will not rush to failure. The transition will be based on meeting standards, not on a timeline.”

He was commenting on a New York Times story Sunday that was the first to report prison facilities wouldn’t be handed over until Iraqi officials improved standards.

Prisons have been one of the sore points between the Shiite Muslim majority and Sunni Arabs, a long-dominant minority that saw its power evaporate with Saddam Hussein’s ouster. U.S. officials are pushing to heal the rift as a way to weaken support for the Sunni-led insurgency.

U.S. soldiers secure the area around an Abrams tank that caught fire after a U.S. convoy was targeted by a roadside bomb Sunday in the center of Baghdad, Iraq, according to Iraqi police.

U.S. Ambassador Zalmay Khalilzad said earlier this month that at least 120 abused prisoners had been found inside two jails controlled by Shiite-run Iraqi Interior Ministry.

Sunni Arabs long have complained about abuse and torture by Interior Ministry security forces. Interior Minister Bayan Jabr contends torture allegations have been exaggerated by people who sympathize with insurgents.

Johnson said that in preparation for the eventual handover of prisons, the U.S. Department of Justice is training Iraqi prison guards. About 300 have completed the course, he said.

In ongoing violence, the U.S. command reported that two American soldiers were killed by bombs Sunday. No other details were immediately released, and it was not clear if they died in the same incident.

A suicide car bomber slammed into two Iraqi army vehicles in central Baghdad, killing five soldiers and wounding seven police and civilians, police Maj. Mohammed Younis said. A second suicide car bomb targeting Iraqi police in Baghdad wounded four officers.

Bombings and gun attacks killed at least 11 more people elsewhere in the capital, Kirkuk, Mosul and Jbala, authorities said.